You may be familiar with the phrase ‘Dunbar’s Number’, named after the anthropologist Robin Dunbar and coined in the 1990s. Dunbar’s number refers to the probable limit to the number of social relationships a person can maintain effectively at one time, and is an interesting concept in the Internet age where many people’s online ‘friends lists’ can number in the high hundreds. What would you think Dunbar’s studies into human brain size and social grouping revealed to be the approximate maximum number of sustainable social connections? 300? 500? Maybe 900?